The Undiagnosed Diseases Network (UDN) is a research study that is funded by the National Institutes of Health Common Fund . Its purpose is to bring together clinical and research experts from across the United States to solve the most challenging medical mysteries using advanced technologies.

Through this study, we hope to both help individual patients and families and contribute to the understanding of how the human body works.


Requirements for Online Application

If you decide to apply for this study, you will need to answer a series of brief questions through our application portal, the UDN Gateway (link below), related to the following:

  • Contact information
  • Demographic information
  • Primary licensed healthcare provider information (name, address, phone, FAX, email)
  • Brief medical history questions
  • Previous evaluations
  • Travel limitations

A referral letter from a primary licensed healthcare provider is also necessary in order to submit the online application to the UDN. This referral letter must include:

  • A summary of the applicant’s medical problems
  • Date when symptoms were first noticed
  • Previous diagnoses
  • History of evaluations and testing
  • History of treatments and medications
  • Current medications
  • Family history
  • Healthcare provider’s diagnostic impressions
  • For pediatric patients, prenatal and birth history should also be provided.

We have prepared a sheet of information for you to share with your provider , as well as a set of sample referral letters .

Application review process

After an application is complete and submitted in the Gateway, applicants receive an email notification. The application is then sent to one of the UDN clinical sites to review.

The UDN clinical sites typically contact applicants within one month of application submission to request additional information, such as:

  • Medical records
  • Laboratory studies
  • MRI, X-ray, or CT images (can be sent on CD)
  • Photographs or videos
  • Pathology slides and reports
  • For pediatric patients: growth curves

In order to help with the application review process, you can begin to collect these records now. However, please do not send this information until you receive specific instructions to do so from a UDN clinical site.

After all of the necessary information is received by a UDN clinical site, it typically takes 6-8 weeks for the network to make a decision whether to accept an applicant.

The UDN Gateway

Button to enter UDN Gateway

Contact Info

Hours: Monday – Friday, 9am – 5pm ET
Email: UDN@hms.harvard.edu
Phone: 1-844-746-4836 (1 844 Ring UDN)

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